Carburetor construction



June 12, 1962 v T. M. BALL 3,038,706

CARBURETOR CONSTRUCTION Y Filed June 4, 1959 3 'Sheets-Sheet 1 INVENTOR.7g j Tfra/af MEQ/.

5g #wwwa/4f N12/UVW June 12, 1962 Filed June 4, 1959 T. M. BALLCARBURETOR'CONSTRUCTION s sheets-sheet 2 Il C?? ff jNVENToR. I7'0/11d5M54' ZZ BY l Il June12,1962 T. MBALL 3,038,706

CARBURETOR CONSTRUCTION Filed June 11V 1959 5 Sheets-Skizze?I 3 20 .J2IN V EN TOR.

Y ALW wm I lnite This application relates to improvements in acarburetor for an internal combustion engine.

The demands of modern automobile styling to -lower the vehicle body `andengine hood, together with the advent of the V-8 engine which cannot-feasibly use an updraft type carburetor, have caused considerableattention to be given to the provision of new means for supplying enginefuel in order to avoid the high silhouette of the conventionalcarburetor. Although the modern carburetor has been compacted and itsoverall height has been materially reduced, it is still too high Iforstyling demands. Various types of fuel injection systems have beenproposed to supplant the carburetor, but the cost of such systems hasprevented their acceptance except in the more expensive automobiles.

An important object of the present invention is to provide an improvedlow silhouette carburetor which satisfies the requirements of modernstyling and enables a lowered engine hood without recourse to a fuelinjection system.

Another and more specic object is to provide such a carburetor whereinthe air horn and venturi of the usual inlet air induction systemcomprise a single elbow-shaped tubular conduit wherein the throat of theventuri is downstream of the elbow bend in the conduit and the .air hornis upstream of the bend.

Another object is to provide an improved carburetor structure of theabove character wherein the customary secondary or small venturi mountedto discharge into the throat of the first-named venturi has its inletand discharge openings at opposite sides of the transverse plane throughthe line f the interior angle of the elbow bend formed by the upstreamair horn portion of the inlet conduit.

Still another object is to provide an improved carburetor which isparticularly simple and economical to fabricate and assemble and whereinthe elbow shaped inlet conduit7 together with other portions of thecarburetor body, are readily susceptible of economical manufacture byordinary die-casting operations.

Other and more specific objects are to provide such a carburetor whereinthe venturi portion and a proximate segment of the air horn defining theinterior angle of the elbow bend comprise one integral die-cast section,a segment of the air horn cooperable with the first-named segment tocomplete the tubular air horn comprising another die cast section; andwherein a major portion of the fuel bowl at least up to the fuel levelcomprises an integral part of the first-named section, the fuel bowlcover comprising an integral part of the second-named section.

The short compact design of the elbow-shaped air inlet conduit isillustrated in the drawings by way of example for use with a dualdowndraft type carburetor, although it will be apparent from thefollowing description that the inlet conduit shown could be used witheither a horizontal or updraft carburetor of other than the dual type.When the compact design as disclosed is employed with the dualcarburetor shown, the portion of the inlet conduit that is ordinarilydivided into two parts is relatively short and some of the advantages ofthe dual over the single carburetor are reduced in importance in variousengine constructions.

In order to minimize loss of effectiveness of the customary dualcarburetor, it is another object of the inven- States Patent tion toprovide means for partitioning the inlet conduit into two parts upstreamof the venturi throat and to extend the partition beyond the customarychoke blade in the air horn where required.

Another object is to provide an elbow-shaped air inlet conduit of theabove character wherein curved baffles including a curved choke valveblade are provided adjacent the elbow bend to direct inlet air aroundsaid bend and to provide for a more uniform air flow distribution in theinlet conduit downstream of the bend.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

FIGURE l is a horizontal sectional view through a carburetorconstruction embodying the present invention, taken in the `direction ofthe arrows substantially along the line 1-1 of FIGURE 2.

FIGURE lA is a fragmentary enlarged vertical sectional view taken in thedirection of the arrows substantially along the line 1A-1A of FIGURE l.

FIGURE 2 is a fragmentary vertical sectional View taken in the directionof the arrows substantially along the line 2 2 of FIGURE l.

FIGURE 3 is a fragmentary end view of the air horn taken from the leftend of FIGURE 2.

FIGURE 4 is a fragmentary horizontal sectional view similar to FIGURE l,but taken in the direction of the arrows substantially along the line 44 of FIGURE 5 and showing a modified construction.

FIGURE 5 is a fragmentary elevational view of FIG- URE 4 with portionsbroken away to show details of the choke blade structure. Y

FIGURE 6 is a -view similar to FIGURE 5 showing another modifiedconstruction.

FIGURE 7 is a Ifragmentary horizontal sectional view taken in thedirection of the arrows substantially along the line 7-7 of FIGURE 6.

FIGURE 8 is a view similar to FIGURE 7, but taken in the direction ofthe arrows substantially along the line 8-8 of FIGURE l0 and showingstill another modification.

FIGURE 9 is a fragmentary elevational view of the left end of FIGURE 8.

FIGURE l() is a fragmentary vertical sectional view taken in thedirection of the arrows substantially along the line 10-10 of FIGURE 8.

It is to be understood that the invention is not limited in itsapplication to the details of construction and arrangement of partsillustrated in the accompanying drawings, since the invention is capableof other embodiments and of being practiced or carried out in variousways. Also it is to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.

Referring in more particularity to FIGURES 1 3, a carburetor embodyingthe present invention is illustrated comprising upper and lower die-castbody or housing portions A and B respectively suitably bolted togetherand to a throttle body 15, for example by a plurality of bolts 16. Thelower cast section B includes a fuel bowl 17 spaced from an inlet airinduction passage 18 by a wall 19. A fuel inlet fitting 20 is secured toa side wall of the fuel bowl 17 and provides means for attachment with afuel source for supplying the bowl with fuel. A valve 21 coupled bybrackets 2.3 to a pair of floats 22 within opposite sides of the bowl 17controls the inlet fuel in accordance with customary practice andmaintains a desired fuel level within the bowl 17. L0- cated between thefloats 22 are the piston and cylinder of a fuel accelerating pumpmechanism 24.

A recess 25 formed in the central portion of the wall 19 provides ashelf 26 for a venturi cluster comprising a venturi mounting portion 27seated on the shelf 26 and a pair of small venturis connected with themounting portion 27 by integral portions 29, FIGURES 1 and 1A. Asuitable gasket 27a is interposed between the shelf 26 and base of themounting portion 27. Recessed into the wall 19 and mounting portion 27is a pair of fuel wells 30, each containing a perforated vent orpartitioning tube 31 vented at its upper end to the inlet conduit 18upstream of the small venturis 28. Also extending. into each well 30adjacent the vent tube 31 is an idle tube 32 opening at its lower endinto the well 30. The tubes 31 and 32 are suitably secured to themounting portion 27 to be removable therewith. Exteriorly of each well30 and extending in the wall 19 is an idle fuel conduit 33 whichcommunicates with a continuation 34 thereof formed in the throttle body15 and opens at an idle fuel orifice 35 into one of each of a pair ofdownstream portions 36 of the passage 18. A separate suitable idleadjusting needle valve 37 controls the extent of opening of each orifice35 and is adjusted by screw 38 maintained in adjusted position by spring39.

A pair of tubular idle vent screws 41 vented at their upper ends to anupstream portion of the induction conduit 18 above the venturis 28 arescrewed into the wall 19, each being coaxial with one of each of theidle ducts 33 to comprise an upper continuation of the latter. Anannular recess 42 in the outer portion of the upper end of each screw 41communicates with the bore of the latter tube via transverse ducts 43and also with the upper end of the associated idle tube 32 via duct 44,thereby to complete a pair of idle fuel conduit systems, each extendingfrom the bottom of the associated well 30, tube 32, ducts 44 and 43,tube 41 and conduits 33 and 34 to the corresponding orifice 35.

A primary fuel inlet conduit 45 extends through the base of wall 19 intoeach well 30 and is closed at its right end in FIGURE 1A by a plug 46. Aseparate tubular metering jet 47 having its bore in communication withone of each of ducts 45 is screwed into the base of the fuel bowl 17.The upper portion of each metering jet 47 comprises a guide and thelower portion is provided with transverse ducts 48` opening into thefuel bowl 17 to provide communication between the latter and associatedduct 45. Shiftable vertically within the upper guide portion of each jetstructure 47 is a Wire plunger 49, which preferably comprises a straightlength of piano wire, having its upper end secured to the cross arm 50of a plunger 51. The latter is actuated by a piston within a cylinder 52which is operably connected with the engine intake manifold pressure soas to raise cross arm 50 and the two wires 49 to allow increased fuelflow through the lower ends of the metering tubes 47 into the supplyducts 45 upon an increase in engine load. Conversely, as engine loaddecreases, the wires 49 are lowered to progressively restrict the lowerends of tubes 47 from their ducts 45.

From each fuel well 30, which is supplied by its separate duct 45, fuelis conducted during operation of the engine to one of each of a pair ofmain fuel supply nozzles 53, one discharging into one of each of thesmall venturis 28. The lower end of each small venturi 28 openscoaxially into the throat of one of each of a pair of larger primaryventuris 54 located immediately above the throttle body 15 anddischarging coaxially into a separate induction conduit portion 36 whichcommunicates with certain of the engine cylinders.

In the dual type of carburetor shown, two large venturis 54 are providedside-by-side in the inlet conduit 18, each discharging into a separatedownstream conduit portion 36. Thus during operation of the engine underload, the inlet air flow through the venturis 28 draws fuel from thewells 30 through the nozzles 53. The upper openings of vent tubes 31 tothe induction conduit 18 upstream of the venturis 28 results in adownward air ow through the vent tubes 31 and thence out the number oflongitudinally spaced openings therein into the respective well 30,thereby to aerate the fuel within the wells 30 and lower the effectivefuel head therein, thereby to facilitate fuel flow up to and out ofnozzle 53. The structure described thus far may be conventional ifdesired and is accordingly not described in further detail. Referencemay be had to applicants Patent Number 2,966,344 for a more. detailedexplanation of the carburetor structure illustrated.

Immediately upstream of the two large venturis 54, the inlet conduitportions 36 merge into the single conduit 18 which turns sharply at aninterior angle 55, FIGURE 2, and provides a lower segment 56 of anelbow-type air horn integral with the venturis 54 and fuel bowl 17. Asillustrated in FIGURE 3, the lower air horn segment 56 is channel-shapedin its vertical transverse section and opens upwardly.

The die cast section A comprises a cover 57, see also FIGURES 4 and 5,for the fuel bowl `17 and an integral fiange 58 which depends from thecover 57 toward wall 19 to effect separation between the interior of thefuel bow-l 17 and the induction conduit 18, FIGURE lA. A gasket 59 ispreferably employed between the fuel bowl 17 and its cover 57 to effecta leak-proof seal. Integral with the cover 57 is an upper air hornsegment 68 which cooperates with the lower segment 56 to complete thetubular ai-r horn indicated. Where desired, the gasket 59 is extendedthe length of the air horn at the juncture between tlle segments 56 and68. In this regard, it is to be noted that the line of juncture betweenthe two air horn segments is coplanar with the juncture between the fuelbowl 17 and its cover 57 and is preferably above the normal fuel levelin bowl 17. The left end or mouth of the air horn is flared at 61 and isprovided with a plurality of reinforcing webs 62 for attachment with aconventional air filter.

Extending in the vertical mid-plane of the air horn from the upper andlower Vsegments 60 and 56 respectively are septums 63 and 64 which meetat a tongue and groove juncture 65 approximately at the level of thegasket 59. The lower septum 64 extends to the top of a septum 66 whichdenes the body of cast section B and separates the two venturis 54. Theair horn segments 56 and 60 are provided with lateral flats 67 adjacenttheir juncture and with upper and lower ats 68 to facilitate mountingaud operation of a choke blade 69. The latter is mounted in unbalancedposition on a pivotal shaft 70, FIGURE l, which extends transverselythrough the flats 67 in the lower segment 56 and is journalled atopposite sides of the blade 69 in external reinforcing bosses 71integral with the segment 56. In order to enable free pivotal movementof the blade 69, a recess 72 is provided in septum 64 for shaft 7 0 andoppositely directed notches 73 are provided in blade 69 at oppositesides of its pivot axis. The blade 69 is secured to a attened portion ofshaft 76 by screws 74 and is operated manually or automatically inaccordance with conventional practice.

FIGURES 4 and 5 illustrate a structure similar to that in FIGURES l3,but the throttle body is formed integrally with the cast section B. InFIGURE 5, a throttle blade operating lever 75 is adapted to be connectedat 76 to a throttle operating linkage and is secured at its lower end toan extension of throttle Ablade shaft 77 to rotate the latter. The shaft77 extends transversely across the two induction passages 36 to providea common support for two throttle blades 78 secured 4to shaft 77 byscrews 79 within the openings 36 respectively, FIGURE 2. A horizontalconnecting link 80 is pivotally connected at opposite ends to thethrottle lever 75 and to a second lever 81 which is keyed to 'a shaft 82to pivot the latter upon operation of the throttle lever 75. The shaft82 is pivoted on the cast section B and is connected by means not shownto the accelerator pump mechanism 24 in order to supply a charge ofaccelerating fuel to the engine in accordance with customary practiceupon each rapid actuation of the throttle lever 75.

Also as illustrated in FIGURE 5, the septums 63 and 64 are provided withcircular openings 83 Iand 84 which cooperate to provide a completecircular openi-ng for a `circular partitioning disc 85 mounted on chokeshaft 70.- The disc 85 completely lls the circul-ar opening made by therecesses 83 and 84 and cooperates with the septums 63 and 64 to providea separation between the two 4halves of the -air horn as in FIGURES 1-3,regardless of pivoting of the throttle blade 69a. In this instance,instead of the unbalanced choke blade 69, a balanced circular chokebl-ade 69a is secured to shaft 70 by screws 74 and is particularlyadapted for use in installations where a manual choke is employed. Inother respects, the structure and operation of the carburetorsillustr-ated in FIGURES l-S are the sa-rne, so that corresponding partsare numbered the same in each view.

The septums 63 and 64 shown in FIGURES 1 5 separate the air horn intotwo halves completely from its mouth or upstream opening to thecustomary partition 66 between the two large venturis 54. It has beenfound that such a partition is import-ant forY optimum power and fueleconomy with certain engine types employing the compact or shortenedelbow-type inlet conduit 18. It is customary in the use of dualcarburetors to discharge admixed fuel and air to the engine alternatelyfrom the two venturis 54 with al-ternate linings of the enginecylinders, thereby to minimize interference with the fuel-air llow. Apressure kick-back or impulse through the side of the inlet inductionconduit in communication with the cylinder that is tiring tends tointerfere wit-h the inlet fuel-air flow in the other side of theinduction conduit unless an adequate length of partition is provided inthe air horn upstream of the venturis 54. The length of the partitiondepends upon numerous factors including the size of, the engine, theoverall cross sectional area and length of the inlet induction conduitto the engine, and the valve timing, so that with some engine types ashorter parti-tion as illustrated in FIGURES 6 .and 7 can ybesatisfactorily employed.

In the latter ligures, the upstream edges of the septums 63 and 64terminate at 63b and 64b respectively just downstream of the choke shaft70. In this instance, wherein the choke shaft '70 extends through thelower segment 56, the lower septum 64 is notched at 86 to provideadequate clearance for the shaft 70. Also the choke blade 6%, comparableto the blade 69, is notched at '13b in order to provide clearance forthe septums 63 and 64 upon pivoting of blade 69,5. In other respects,the structure and operation of the carburetor ilustrated in FIG- URES 6and 7 and the same as described above in regard to FIGURES l-5, so thatcorresponding parts are numbered the sante in all views.

FIGURES 8-10 illustrate an even shorter air horn partition wherein theupstream edges of the septums 63 and 64 terminate at 63C and 64Crespectively, FIGURE l0, immediately downstream of the innermostprojection o f the choke blade 69C when the latter is in the openposition. In' this instance the upstream or leading edges 63C and 64Ccooperate to provide a partition which declines from the top to thebottom of the air horn in the upstream direction. Thus the uppermostportion of the leading edge of the .septum 63y is downstream of thechoke blade 69e and the lowermost portion of the septum 64 extends to aposition upstream of the choke blade when the latter is in its wide openposition. By this structure a compromise partition length is achievedwithout necessitating a notch-ed choke blade.

Also as illustrated in FIGURE l0, the downstream edge of choke blade 69Ccurves downwardly to effect a baille action which assists the directionof the inlet air llow around the bend of the air horn when the chokeblade 69C is at its open position. Conforming substantially to the uppercurvature 55C of the elbow bend, a fixed baille 87 extends transverselyacross the upper portion of induction chamber 18 at a location betweenthe trailing curved edge of blade 69c and said upper curvature 55C. Asillustrated in FIGURES 8 and l0, the opposite lateral edges of thecurved baille 87 are provided with integral projections 88 confinedwithin a pair of parallel supporting slots S9 formed at opposite sidesof the upper air horn segment 6G. The slots 89 decline in a downstreamdirection and open at the lower edge of the segment 60. Prior toassembly of the segments 60 and 56, the projections 88 of braille 87 areinserted into the lower ends of the slots 89, whereupon after assemblyof the segments 56 and 68', the lowermost of the lateral projections 88will rest upon the upper edges of segment 56 and hold the baille 87 inposition. The trailing edge of baille 87 is slotted centrally at 90 inorder to receive the lower septum 64. The baille 87 with its integralprojections 88 can be feasibly stamped from sheet metal, the projections88! being twisted angularly with respect to the curvature of the bailleso as to fit snugly within the opposed straight slots 89.

The curved baille 87 or curved'chotke blade 69C can be employed in `anyof the above-described structures and are particularly useful withcertain engine installations for assisting the necessary change ofdirection of air flow around the bend of the inlet conduit l8r.

I claim:

l. In a carburetor construction for an internal conibustion enginehaving `air induction conduit means, an elbow-shaped tubular inletconduit for said carburetoi having a venturi portion adapted forcommunication With said induction conduit means to discharge thereintodownstream of the bend in the elbow of said inlet conduit and having anair horn portion adapted for communication with an inlet air supplyupstream of said bend, said inlet conduit comprising two cast sections,one of said sections including said venturi portion, said one sectioncomprising the interior angle of said bend and a segment of said airhorn portion extending longitudinally of the latter, the upstream end ofsaid venturi portion flaring endwise and comprising a rounded interiorsurface Iat the bend of said elbow merging with said longitudinallyextending air horn segment, the other section including a segment ofsaid air horn portion cooperating with the first named segment tocomplete a tubular air horn.

2. In a carburetor construction for an internal combustion engine havinga down-draft air induction conduit means, an elbow-shaped tubular inletconduit for said carburetor having a downstream venturi portion belowthe bend of the elbow and adapted for communication with said inductionconduit means to discharge thereinto, said inlet conduit also having anupstream air horn porton above said bend and adapted for communicationwithV an inlet air supply, said inlet conduit comprising tw'o castsect-ions, one of said sections including said venturi portion, said onesection comprising the interior angle of said bend and a segment of saidair horn portion extending longitudinally of the latter, the bottom ofthe interior of said segment being level with the top of said venturiport-ion and merging thereinto at a rounded surface comprising a flaredupper end of said venturi portion, the other section including a segmentof said air horn portion cooperating with the first named segment tocomplete a tubular air horn.

3. In a carburetor construction, a throttle body having a down-draftinduction conduit portion therein, an air inlet conduit secured to saidthrottle body comprising an elbow having a downstream venturi portion incommunication with said conduit portion to discharge thereinto and alsohaving an upstream tair horn portion extending transversely of saidventuri portion, said inlet conduit cornprising two sections, one ofsaid sections being proximate and above said throttle body and includingthe interior angle of said elbow and a segment of said air horn openingin the direction axially of said induction conduit portion and upwardlyfrom said throttle body, the bottom of the interior of said segmentbeing `level with the top of said venturi portion and merging thereintoat a rounded surface comprising a flared upper end cf said venturiportion, the other section including .a segment of said air horn openingin the opposite direction, said segments cooperating to complete atubular air horn, said one section also including a fuel bowl, and saidother section also including a fuel bowl cover, said segments extendinglongitudinally of said `air horn and meeting adjacent the plane of theinterior surface of said fuel bowl cover.

4. In 4a carburetor for an internal combustion engine having airinduction conduit means, a tubular elbowshaped air inlet conduit forsaid carburetor having a pair of venturi throat portions arrangedtherein side-by-side downstream of the elbow bend for communicating withsaid induction conduit means, said venturi throat portions being onopposite sides of the mid-plane of said inlet conduit containing saidbend, said inlet conduit having an air horn portion upstream of saidbend for communicating with an air supply, said inlet conduit comprisingtwo cast sections, one of said sections including said throat portions,said one section comprising the interior angle of said bend and asegment of said air horn portion extending longitudinally of the latterand defining said interior angle, the other section of said inletconduit including a segment of said air horn portion cooperating withthe first named segment to complete a tubular air horn, each sectionhaving an integral septum parallel to and adjacent said mid-plane, thetwo septums cooperating to partition said air horn into ltwo partsupstream of said venturi throat portions, each part communicating withone of each of said venturi throat portions, a choke valve blade in saidair horn having a pivot axis extending transversely of said septums,said septums extending both upstream and downstream of said blade andbeing recessed to provide an opening conforming to the arc scribed bysaid blade upon pivoting thereof, and a partition element pivotal withsaid blade arranged within said opening to fill the same and comprise acontinuation of the partition effected by said cooperating septums.

5. In a carburetor for an internal combustion engine having airinduction conduit means, a tubular elbowshaped air inlet conduit forsaid carburetor having a pair of venturi throat portions arrangedtherein side-by-side downstream of the elbow bend for communicating withsaid induction conduit means, said venturi throat portions being onopposite sides of the mid-plane of said inlet conduit containing saidbend, said inlet conduit having an air horn portion upstream of saidbend for communicating with an air supply, said inlet conduit comprisingtwo cast sections, one of said sections including said throat portions,said one section comprising the interior angle of said bend and asegment of said air horn portion extending longitudinally of the latterand defining said interior angle, the other section of said inletconduit including a segment of said air horn portion cooperating withthe first named segment to complete a tubular air horn, each sectionhaving an integral septum parallel to and adjacent said mid-plane, thetwo septums cooperating to partition said air horn into two partsupstream of said venturi throat portions, each part communicating withone of each of said venturi throat portions, and a choke valve blade insaid air horn having a pivot axis transverse to said septums, said bladehaving a curved downstream portion effective in the open position todeflect incoming air around said bend.

6. In a carburetor for an internal combustion engine having airinduction conduit means, a tubular elbowshaped air inlet conduit forsaid carburetor having a pair of venturi throat portions arrangedtherein side-by-side downstream of its elbow bend for communicating withsaid induction conduit means, said inlet conduit having an air hornportion upstream of said bend for communieating with an air supply, saidinlet conduit comprising two sections, one of said sections includingsaid throat portions, said one section comprising the interior angle ofsaid bend and a segment of said air horn portion extendinglongitudinally of the latter and defining said interior angle, the othersection of said inlet conduit including a segment of said air hornportion cooperating with the first named segment to complete a tubularair horn, and a choke valve blade in said air horn having a pivot axistransverse to said air horn, said blade in the open position having acurved downstream portion extending into the region of curvature ofincoming air around said bend and being effective to deliect saidincoming air around said bend.

7. In a carburetor for an internal combustion engine having a down-draftair induction conduit means, a body casting for said carburetorcomprising a fuel bowl and a tubular elbow-shaped air inlet conduit,said inlet conduit having a venturi arranged therein below anddownstream of its elbow bend for communicating with said inductionconduit means and also having an air horn portion above and upstream ofsaid bend for communicating with an air supply and extendingtransversely of said venturi, said casting comprising one sectionincluding said venturi throat portions, a segment of said air hornportion extending longitudinally of the latter and defining the interiorangle of said bend, and a portion of said fuel bowl proximate said airinduction conduit means, the bottom of the interior of said segmentbeing level with the top of said venturi and merging therewith at arounded surface comprising the enlarged upper end of said venturi, saidcasting comprising another section including a segment of said air hornportion cooperating with the first-named segment to complete a tubularair horn and also including a cover for said fuel bowl, a separatesecondary venturi mounted in said venturi and having its inlet andoutlet openings located respectively above and below said bottom of saidfirst-named segment, and a fuel feed nozzle in communication with saidfuel bowl and discharging into said secondary venturi.

8. In a carburetor for an internal combustion engine having an airinduction conduit means, a tubular elbowshaped air inlet conduit forsaid carburetor having a pair of Venturi throat portions arrangedtherein side-by-side downstream of the elbow bend for communicating withsaid induction conduit means, said venturi throat portions being onopposite sides of the mid-plane of said inlet conduit containing saidbend, said inlet conduit having an air horn portion upstream of saidbend for communicating with an air supply, said inlet conduit 50comprising two cast sections, one of said sections including said throatportions, said one section comprising the interior angle of said bendand a segment of said air horn portion extending longitudinally of thelatter and defining said interior angle, the other section of said inlet5 conduit including a segment of said air horn portion cooperating withthe first named segment to complete a tubular air horn, a partitionseparating said air horn into two parts upstream of said venturi throatportions, each part communicating with one of each of said venturithroat portions, a choke valve blade in said air horn having a pivotaxis extending transversely of said partition the latter being recessedto provide an opening conforming to the arc scribed by said blade uponpivoting thereof, and a partition element pivotal with said bladearranged within said opening to fill the same and comprise acontinuation of said partition.

9. In a carburetor for an internal combustion engine having airinduction conduit means, an air inlet conduit o for said carburetorhaving a pair of venturi throat portions arranged therein side-by-sidefor communicating with said induction conduit means, said inlet conduithaving an air horn portion for communicating with an air supply, apartition separating said air horn into two 75 parts upstream of saidventuri throat portions, each part communicating with one of each ofsaid venturi throat portions, a choke valve blade in said air hornhaving a pivot axis extending transversely of said partition, the latterbeing recessed to provide an opening conforming to the are scribed bysaid blade upon pivoting thereof, and a partition element pivotal withsaid 'blade arranged within said opening to ll the same and comprise acon tinuation of said partition.

References Cited in the le of this patent UNITED STATES PATENTS JohnsonApr. 19, 1932 Mock et a1 Oct. 31, 1933 Johnson Nov. 7, 1933 Mock Mar.27, 1945 Ericson Oct. 9, 1945 Winkler Apr. 1, 1958

